SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1c04fdb7260809c32e2572a78188ea0c7a0a23ebe92ca7f6b25fa174217f1283' 
  AND token = 'xf19YRPIRoTfmZnP4E3EdNhYff7plpk+UJoPY12wewc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}